by Haley Blum, USA TODAY

by Haley Blum, USA TODAY

Jessica Simpson has reached her weight-loss goal, and she's showing it off.

The 33-year-old mom of two posted photos of her fit body on Instagram Thursday, first in a form-fitting white dress on the set of a new Weight Watchers commercial and then in a plain white T-shirt for a selfie.

"First time rocking a white dress this year ...but not the last!!," she captioned the first photo. "Thanks @weightwatchers!"

In the second photo, she added, "...AND a white T-shirt!! #goalreached."

Simpson is a spokesperson for the weight-loss company and has appeared in ads over the course of her healthy journey. She gained weight while pregnant with 20-month-old daughter, Maxwell, and 8-month-old son, Ace, whose adorable photos she posts on Instagram.

"Being pregnant for two years took a toll," Simpson told USA TODAY in December.

With a wedding coming up - she's engaged to retired NFL player Eric Johnson - she says hitting the gym and watching what she eats will continue to be a priority.

"Working out and being active overall makes me a happier person to be around," she said. "I let out so much more anxiety if I go out and walk and talk to Eric, who is basically my therapist on our walks."